1. Field of the Invention
This invention relates to a method and apparatus for verifying the integrity of a Smart Card.
2. Description of the Related Art
"Smart Cards" are cards normally of a plastics material having embedded in them circuitry and active or passive components which carry information in coded form. These cards are used as enabling devices and can have the information in them altered or changed at will and information can be read out from the card to check an identity or authority when the card is used as a key or pass card.
Although some Smart Cards may include their own power source such as a built in battery or may be activated externally by an induction or capacitative connection many rely on actual physical connections to host device. The present invention is particularly concerned with such cards which are hereinafter referred to as `Contact Smart Cards`. Since the cards may be used as a money substitute or for enabling a privileged access it is important that only truly authenticated cards are able to be used and that false cards or simulations of card effects are detected and are unable to be used. The cards may, for example, be used in such areas as to permit travel on a transit system or to operate decoders for pay television or in public telecommunication networks or for the access to personal and confidential information.
With the increasing reliance on Smart Cards in such areas, it is important that the host system cannot be deceived by anything which is not a genuine Smart Card, issued by the controlling authority.
The possibility of simulating the behaviour of certain types of Smart Cards has been demonstrated, using only a basic circuit consisting of easily available electronic components. This opens the way for a person with a basic knowledge of electronics to by-pass payment or compromise security.
Knowing that it is possible for an unscrupulous person to build such a circuit, which can be functionally indistinguishable from a genuine card, some means is required to detect whether the Smart Card presented is in fact genuine, or is a simulated card.
An effective way of distinguishing between genuine Smart Cards and Smart Card simulating circuits would be to detect the presence of the wires which would be required to connect such a circuit to the Smart Card reader contacts.
Traditional methods of detecting the connecting wires have involved coils mounted around the card reader entry slot. This involves the difficulty and expense of mechanically mounting these coils. These methods can also be overcome by reducing the amount of metal used in the connecting wires such that the response is negligible.